Old EV Batteries May Power Homes One Day

Partially depleted Chevy Volt batteries might find new life one day in energy storage applications outside the vehicle, such as parceling out power to homes during blackouts.

General Motors has entered a pilot program with the residential energy provider Duke Energy to put lithium-ion batteries to work in grid test demonstrations. To learn more about the concept's viability, Duke plans to use a module incorporating five Chevy Volt batteries. "Duke will look at the cost efficiencies and utility of the system to determine whether they can use it in more applications in the future," Kevin Kelly, a spokeman for GM, told us.

Though little is known about Duke's test application, GM says that five Volt batteries, packaged together in a single module, could provide two hours of electricity for five average American homes. In a recent off-grid demonstration using an energy storage inverter from ABB, a prototype module supplied 50kWh of energy to support lighting and audiovisual equipment.

A module with five used Chevy Volt batteries could provide two hours of electricityto five average American homes.(Source: GM)

GM engineers say Volt batteries could supply an additional 15 years of energy, even after the cells can no longer be used in a vehicle. The key to such ongoing capability is the way EV batteries are being designed and used in electric cars. To minimize warranty costs, today's EV manufacturers typically make their batteries much larger than they need to be. The batteries operate within large buffer zones, which enhance their automotive life by preventing them from reaching a fully charged or fully discharged state. As a result, the batteries may still have 70 percent of their capacity remaining when they reach the end of their useful automotive life.

Nissan Motor Co., maker of the Leaf electric car, is investigating using its 24kWh lithium-ion batteries in similar applications.

Industry analysts say the concept needs years of testing before it can be called viable. "We're still in the early days of electric vehicle battery usage," Cosmin Laslau, an analyst for Lux Research, told us.

It's probably going to be another five to 10 years before we can fully quantify and understand the wear on the batteries. Right now, we don't really know what a Chevy Volt or Nissan Leaf battery would look like after a decade of real-world use. Even with accelerated testing, it's still difficult to predict.

GM envisions the batteries serving in residential subdivisions near local transformers to provide energy for homes during blackouts or brownouts. Utilities might also use the batteries as a form of storage to back up intermittent renewable sources, such as wind and solar. GM hopes the concept will help delay the inevitable recycling of used EV batteries. "The last thing we are looking at today is recycling," Kelly said. "Secondary life is our focus right now."

Industry analysts say there may be a long wait before anyone knows if utilities will accept the concept. "There's a limited volume of EVs out there right now," Laslau said. "There are thousands of batteries available, but in the grand scheme of things, that's a drop in the bucket for the grid. Until EV sales really pick up, it's going to be hard to get the attention of the major players in the grid space."

Cap'n, that is a great idea. Even if it is only an interim solution, it keeps the batteries useful even after their first use is done. This also makes it an inexpensive way to transition the electric grid to a more distributed system, which is important to the use of wind and solar.

What really encourages me is the clever ways which engineers find to resue and extend. In the Wall Street Journal yesterday there was an article about a company that is extracting additional iron ore from mine trailings using magnets. If there is value in a device or material then an engineer will find a way to take advantage of it.

Naperlou, for the moment, the effect of this may be virtually non-existent because there are so few lithium-ion electric car batteries out there. There aren't many EVs out there, and the few batteries that are available for this purpose will probably be in the vehicles for another six or seven years. At some point, though, this idea will be a viable one. It means the batteries won't have to be recycled for an additional 10-15 years after their vehicles lives are finished.

As a free market advocate, the time frame you mention does not bode well for continued private research. In this case, I do support government helping (short-term) to bring this technology to market. The more we can keep these batteries in use, the less likely we will have to deal with potential recycle contamination nightmares.

It also makes sense if a car buyer can cost justify the more expensive batteries across 10 to 15 years (powering their home as well as their commute).

Reuse is a good idea. One needs to compute the cost for distribution and redeployment. I doubt seriously that many home owners or neighborhoods are going to foot the cost for the alternate battery source for their cabin in the woods for infrequent power outag usage when one can simply buy a generator. I personally would buy a generator long before considering putting up a shack to house old battery packs in hopes that I might be productive during a short term power outage.

A search of the internet yielded the following analysis giving a bleak outlook for the recycling of the raw materials from a lithium ion battery based on material costs and difficulty of the process.

Weldon, good points. I worked at a software company with a guy who had a business recycling the metals from computers. There are small amounts of gold, etc. in the semiconuctors and circuit boards. The business failed (as most did at the time, 20 years ago, or so) becuase the price of the recovered commodities went way down. The costs were high as well. This is a tough business.

I would see the real market for the batteries being the utilities or renewable energy providers. They might fit into a substation or on a wind farm. I agree that there would be little or no market at the individual level.

This is a great idea. I am an avowed skeptic, but this is something I can agree on. Owning an electric car, knowing I could re-use the batteries at home for energy storage, makes economic sense. Now I can start to calculate payback not only in gas mileage, but home energy use as well.

Like to see more information and exploration of what happens to these batteries when the vehicle ceases to be drivable.

Agree that this is really a fantastic idea. So much better to reuse these types of batteries past their expiration date in a car rather than have them end up in a landfill somewhere. It's really inspiring to see researchers really working to find new and invent ways to use and reuse energy sources.

Just remember, these things are very high voltage. My mechanic is afraid to work on electric assisted cars for that reason. It is one thing to work with 110/220, but 700 volts or whatever they are? You have to know what you are doing, plus how many inverters work with high DC voltages?

The article says the GM demo was done with an ABB "energy storage inverter" which sounds by the name at least to be targeted at this specific app. My neighborhood could definitely use one of these modules near the local transformer.

Yes, and I'll use the tyres and fill them with dirt for home constructions and the glass for my skylight while I sit on the comfy seats. Get real. Recycled car parts is an idea with very few uses in the real world.

When the time comse that I really need to use old car batteries for power, I 'll simply steal yours...along with your baked beans and ammo.

I tend to be cynical about this sort of re-application in general, but in this specific case it addresses actual concerns. If I were a "greenie" and building a wind or solar generator for my home, I'd certainly prefer a single recycled EV battery over a dozen or so 12V auto batteries for storage. Apart from the electrocution-causing high voltage, this would be a do-it-yourselfer's dream, if they could find a cheap EV battery to buy. Imagine a remote vacation cabin in the woods that you use a few times a year. Such a battery with a green generator would mean the home could be completely off the grid, with cost-free power and no fuel storage. Makes a great place to hide during the zombie apocalypse, too! (that'll be the tag line for a late-night infomercial)

I'm not sure the government has a central place in this - I'm also mainly a free-market guy. I could see brokers set up to find and distribute the recycled batteries for a profit (or just ebay). Transport's gonna be huge, unfortunately, adding to resale cost. But there are lots of individual homeowners installing solar panels these days - some might be set up well enough to use these for storage- maybe a bit of overkill, but... The lead-time on this might be simply waiting for EVs to crash.

One of the options the Chev volt could provide is having a 20 amp or 30 amp 120 v or 240 v outlet as an option. then in an emergency the car could be used to power the refigerator etc. This would be a very inexpensive option probably and the system already has the inverter, smarts to generate electricity.

This option would make the purchse of a hybrid much more attractive and it would provide an additional use for the car in an emergency.

Also If the Hybrid SUV or pickup could provide 30 amps at 240 then they could power most small RV's and or provide power at a job site. using the hybrid with the battery would also provide a very efficient generator system as the engine would only run intermittantly as needed to recharge the battery.

this concept is being evaluated for hybrid vehicles in the army as then the vehicles could be used as a generator in camp etc without needing another seperate generator system.

The problem with any battery no matter what the chemistry is that when it starts to degrade it not only has reduced capacity but reduced efficiency. Keeping cells matched in an older pack becomes increasingly difficult which contributes even more to the impact on pack capacity and efficiency - a pack is only as stong as its weakest cell. Once a battery exhibits a decline in capacity, it's ability to continue delivering Ah at any level is very limited - the number of charge/discharge cycles from 80% capacity to 50% is a small fraction of what 100% to 80% was. The step from 50% to "resistor" is very few useful cycles and very low efficiency. I guess a use model could be created where even at such reduced capacity and efficiency these packs can still useful but I believe it would be a pretty niche application. That's great for niche applications but not where the problem really needs to be solved, namely $/Ah for new packs. "Recycling" a $25,000 EV pack so that you can help run a few homes' A/C during peak demand seems more like a solution in search of a problem. I predict that the overhead (transportation, testing, repackaging, integration and failure mitigation) in processing these expired packs into an alternate application will far outweigh their value in Ah delivery.

You raise a bunch of good points, Contrarian. Ultimately, this technology might just appeal in niche applications. I keep thinking of California's "one-third renewables" energy mandate. Could that be a niche opportunity?

When I first read this, I thought of The Onion (http://www.theonion.com/articles/chevy-to-sticker-cars-environmental-impact,27222/). The claim: "We are going to turn junk into useable energy". The reality: Junk meets no standards. If this were a viable idea why not recycle our lead-acid car batteries right now? If you guessed that it would not be a viable business you would be correct. Only the government (subsidized by tax dollars) could provide such systems. A few volt car have burned down houses already, now we can do the same to whole subdivisions!

I agree with wlawson and contrarian. If they put an inverter in the volt we would have emergency power available. A thousand dollar option to replace a $500 home generator. Current gas equipped cars could be sold with optional generators today on PTOs at far higher efficiency.

Then after all this, the batteries will still need to be scrapped. In my backyard or yours?

I have often thought it would be better to have a battery or bank of batteries supplying power to an inverter or dc motor running a ac gnerator. The batteries would be charged off the grid. In case of a power failure the ac power would provide the power to led lighting. The other necessary appliances would be provided power by switching between them. I can not think of any home appliance in a home that would require more than 10 amps of power at one time. I am quite sure you could operate the necessary appliances for several days off the grid. This system would go a long way to providing necessary confort to a home owner in the event of a power outage.

So now we are told that an EV battery may still have 70% of it's useful capacity left when it is no longer suitable for automotive use. That is one more very good reasons why the electric vehicle as we now know it is a poor choice. The other poor choice is the amount of affort to recover the cells and assemble them in a useable array. OR, is the plan to simply plug in the retired EV batteries with no modifications to them at all? That would be easy but probably have some problems after a while.

Now on that other assertion about using them for off-grid energy systems, they still need to be charged with energy that comes from someplace, and the conversion of "freee" energy into a form that we can utilize is not free, it is quite expensive. That has not changed yet. The main reason that we use hydrocarbon based energy is that we know how to do it, and it seems to be cheaper and simpler than using other forms of stored energy.

One more thing is that the gas engine in your car can deliver the same power until the tank runs dry as it can when the tank is just filled. It does not work that way for any battery yet, although some are better than others.

I, too, was amazed by the 70% figure, WilliamK. I knew that EV batteries are built with a buffer to prevent overcharging and undercharging, but it it still shocked me that 70% of the capacity would remain. Regarding modifications: When I asked if the cells-only would be used or if the pack with its entire cooling system would be used, GM said it wasn't sure. There are a lot of aspects to this which still need to be studied.

This looks like an attempt to justify a problem at the tax payer expense. First, the subsides given to bailout GM then to buy a technology in a car that isn't all that green. The resources to mine the Lithium, put it in a battery, and charge it is already a sham. Now it looks like the government is throwing dollars at something not to recycle it but to justify what to do with the old batteries when the answers required are not technical they're political. I do agree we should look into recycling the batteries but I am more inclined to let the free markets dictate those solutions.

I'd rather be using the glass-encased lead-acid cells they used in the DCO's for POTS. With proper care and feeding, those things will last decades. I have yet to hear of a lead-acid cell catching fire while in use. (We'll neglect the knuckleheads who don't know how to properly jump-start a vehicle and end up with a faceful of sulfuric acid.)

As for lithium-ion batteries, a very nice combat submersible for the Navy SEALs was destroyed due to a run-way Li-ion cell.

My experience with encased flooded lead acid batteries is that they last about 10 to 15 years max - not 20 as advertised. They are extremely heavy and require regular maintenance by trained techs. Cracked cases resulting in acid leaks are a nightmare.

I have not had direct experience with the Pb-acid batteries in a telecom environment, but the pair of GC2 flooded batteries I use for house batteries for my travel trailer lasted for a decade of heavy use and a serious dose of benign neglect with a crappy OEM-spec charger. These things sit exposed on the tongue of my trailer year-round. We deep discharge them when we dry-camp and then cook the cells when we're hooked up to 'shore power'. We use our camper year-round in all climate conditions. Ideally we should've topped them off with distilled water but I'd say I only did that for the first couple of years then got lazy. My wife never checks the electrolyte, so if she's camping without me, those black blocks on the tongue are never even looked at.

I want to believe that the glass-encased cells would perform significantly better in a stationary application, controlled environment, proper charging and discharging, etc.

But I have to defer to those who live with these things day in and day out.

Thank you for commenting on my post. Although the chemistry is the same, deep discharge batteries probably contain a greater amount of raw material per unit of capacity than flooded cells. The flooded batteries I am familiar with are kept in trickle mode all the time and are discharged only briefly in use and discharged deeply in testing. They also generate copius amounts of hydrogen which is a problem when installed indoors. Every design has its purpose. Lead acid chemistry is cheap and has a fairly good power density.

Hi Marty, The DCO's I'm familiar with (military installations), the battery drives the board directly so it is always "on-line" and the chargers provide just enough current to drive the load plus a little extra for occasional conditioning and maintenance. My understanding was these things were designed with thicker plates instead of greater surface ares for longer duration discharge at the expense of peak current like what is used in a starting battery for a vehicle. I was never at any one place long enough to experience the lifecycle replacement of the cells. I've long since left that environment so I'm not sure what's currently done in the exchanges.

You're definitely on the money regarding the cost per W-hr. Pb-acid beats Li-ion hands down, but not on weight where in a transportation environment lithium based batteries are more attractive from that point of view. Plus lead-acid batteries are much easier and efficient to recycle.

My choice for best-value distributed energy storage would be lead-acid even with its warts. (Electrolyte containment and proper venting are the two biggest bugaboos.)

That's an amazing run with flooded lead-acid batteries... I end up replacing my pop-up's marine deep-cycle battery every 3 years or so, even when being careful to keep it charged when not in use. Maybe I need to find a better brand....

The original Group 27 battery that came with our trailer didn't last a hoot. My dad gave me two Sam's Club GC2 that he had used as house batteries on his boat. He had used them for a couple of years before we got them. He swapped out the 8D house batteries on his boat for GC2 because a GC2 is about 1/3 of an 8D but when you're trying to load them on your boat, get them down the hatch and into the engine compartment, the 8D's were a literal pain in the back. He had to create rigging to remove the 8D's. The GC2's he could man handle. Plus on a cost basis, GC2's are about $80 each at Sam's versus about $400 for an 8D. It takes about three GC2 to store the same energy as one 8D. Keep in mind a GC2 is a 6V battery so you'll need two in series for 12V applications.

You're right about the fire risks of lithium-ion, J Williams. As material scientists like to say, "The chemistry is edgy." That's why I find it hard to believe they would use lithium-ion cells in these applications without including the battery pack cooling systems.

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